Viscous-material filling method

ABSTRACT

A method for transferring a viscous material into a syringe that has a plug dividing a syringe interior into a first sub-chamber and a second sub-chamber, where a radial clearance exists between the plug and the syringe, includes transferring the viscous material from a container into the first sub-chamber to fill the first sub-chamber while allowing air initially present within the first sub-chamber to flow into the second sub-chamber via the radial clearance, and flowing a first volume of the viscous material into but not through the radial clearance such that the viscosity of the first volume of the viscous material and the radial clearance cooperate to block a flow of a second volume of the viscous material into the radial clearance and prevent the second volume of the viscous material from leaking from the first sub-chamber into the second sub-chamber.

TECHNICAL FIELD

The invention relates to techniques of transferring and filling aviscous material from a container into a syringe, and more particularlyto techniques of preventing the ingress of gas into the viscous materialduring the filling process.

BACKGROUND ART

It is known that viscous materials are utilized in some industries. Suchapplications include sealants for mechanical or electrical components,adhesives, pastes for use in forming electrical or electronic circuits,solders for use in mounting electronic components, etc. Such viscousmaterials are used in the aerospace industry, the electrical industry,the electronics industry, etc.

In some cases, a viscous material is transferred and filled from acontainer into a syringe, in order to improve the convenience ofapplying the viscous material to a target object. In these cases, duringthe filling process when the viscous material flows and is divided, itis possible that gases will be unintentionally entrapped in the viscousmaterial. In addition, in case gases have been undesirably entrapped inthe viscous material, there are the problems that the quantities of theviscous material intermittently dispensed from the syringe willundesirably vary with time, and that, at the ultimate stage when theviscous material is used after being cured, undesirable voids will beformed within the cured viscous material.

In an attempt to solve these problems, Japanese Patent ApplicationPublication No. 2002-80005 discloses a prior-art technique of evacuatingan air-tight chamber in which a container and a syringe are placed, tothereby evacuate the interiors of the container and the syringe, andextruding a viscous material from the container to the syringe byapplying an external mechanical force to the viscous material within thecontainer while the interiors are subjected to a vacuum.

SUMMARY OF THE INVENTION

However, the disclosed prior-art technique requires a filling device,which fills the syringe with the viscous material, to have an air-tighthousing for holding both the container and the syringe, in order toprevent the ingress of gas into the viscous material during the fillingprocess. For this reason, this prior-art technique tends to increase therequired size of the filling device and the part count of the fillingdevice; consequently, the required weight and cost of the filling devicetend to increase.

Therefore, the invention has been created to provide techniques oftransferring and filling a viscous material from a container into asyringe, without requiring the provision of a housing for holding boththe container and the syringe in an air-tight manner, while preventingthe ingress of gas into the viscous material during the filling thesyringe with the viscous material.

According to one aspect of the present invention, a method is providedfor transferring and filling a viscous material from a container into asyringe, comprising inserting a plunger into the container; inserting afirst plug, which permits gas flow in one direction, into the syringe;connecting the container and the syringe with each other; inserting arod into the syringe such that the rod engages with the first plug; andpushing the plunger within the container, thereby extruding the viscousmaterial from the container and transfer and filling the extrudedviscous material into the syringe.

According to the present invention, the following modes are provided.These modes will be stated below such that these modes are divided intosections and are numbered, and such that these modes depend upon othermode(s), where appropriate. This facilitates a better understanding ofsome of the plurality of technical features and the plurality ofcombinations thereof disclosed in this specification, and does not meanthat the scope of these features and combinations should be interpretedto limit the scope of the following modes of the invention. That is tosay, it should be interpreted that it is allowable to select thetechnical features, which are stated in this specification but which arenot stated in the following modes, as technical features of theinvention.

Furthermore, reciting herein each one of the selected modes of theinvention in a dependent form so as to depend from the other mode(s)does not exclude the possibility of the technical features in thedependent-form mode from becoming independent of those in thecorresponding dependent mode(s) and to be removed therefrom. It shouldbe interpreted that the technical features in the dependent-form mode(s)may become independent according to the nature of the correspondingtechnical features, where appropriate.

(1) A method of transferring a viscous material from a container into asyringe for filling the syringe,

wherein the container comprises:

a container housing;

a container inner chamber that is defined within the container housingfor holding the viscous material; and

first and second openings that are defined within the container housingin fluid communication with the container inner chamber, and

the syringe comprises:

a syringe housing;

a syringe inner chamber that is defined within the syringe housing, intowhich the viscous material is to be transferred from the container forfiling the syringe; and

third and fourth openings that are defined within the syringe housing influid communication with the syringe inner chamber,

the method comprising:

inserting a plunger into the container through the first opening, withthe container holding the viscous material, to thereby provide acontainer set to be held in position;

inserting a first plug into the syringe so as to be in slidable contactwith the syringe, to thereby provide a syringe set, the first plugwithin the syringe separating the syringe inner chamber into a firstsub-chamber nearer to the third opening, and a second sub-chamber nearerto the fourth opening, the first plug permitting gas flow in a directionfrom the first sub-chamber to the second sub-chamber, preventingviscous-material flow in the same direction, and preventing gas andviscous-material flow in the reverse direction, the syringe set held inposition with the third opening of the syringe removably coupled withthe second opening of the container in a substantially air-tight manner;

inserting a rod into the syringe so that the rod engages with the firstplug, to thereby apply a force to the first plug in a direction thatallows the first plug to be displaced while reducing a volume of thefirst sub-chamber; and

pushing the plunger within the container so as to move the plungertowards the second opening, to thereby extrude the viscous material fromthe container through the second opening, in order to transfer theviscous material from the container into the first sub-chamber of thesyringe for filling the first sub-chamber.

According to this method, before the syringe is filled with the viscousmaterial, when the viscous material flows in the first sub-chamber ofthe syringe from the container, the viscous material compresses a gasconfined in the first sub-chamber, creating a pressure differentialbetween the first sub-chamber and the second sub-chamber within thesyringe, such that the first sub-chamber is higher in pressure than thesecond sub-chamber that is in communication with outside of the syringe.The pressure differential allows the gas within the first sub-chamber toflow in the second sub-chamber via a radial clearance between an innercircumferential surface of the syringe and an outer circumferentialsurface of the first plug, and eventually, the gas is released from thesyringe through its fourth opening.

As a result, according to this method, during the process of filling thefirst sub-chamber with the viscous material, as more viscous material isfilling the first sub-chamber, more gas is released from the firstsub-chamber, preventing the viscous material within the firstsub-chamber from trapping gas.

Further, according to this method, a force is applied to the first plugwithin the syringe in a direction that allows the first plug to bedisplaced while reducing the volume of the first sub-chamber. Theapplied force displaces the first plug towards the viscous material heldwithin the syringe, in other words, the applied force compresses thefirst sub-chamber.

For these reasons, according to this method, the above-mentionedpressure differential is also created by applying the aforementionedforce to the first plug by the rod; therefore a larger amount of thepressure differential is created than if no force were applied to thefirst plug by the rod. Gas flow is facilitated in the direction from thefirst sub-chamber into the second sub-chamber through the radialclearance formed between the inner circumferential surface of thesyringe and the outer circumferential surface of the first plug.

Thus, according to this method, for transferring a viscous material froma container into a syringe for filling the syringe, while preventing theviscous material from trapping gases, there is no need to evacuate theinner chambers within the container and the syringe (especially an innerchamber within the syringe). As a result, ingress of gases into theviscous material is prevented during the process of filling the syringewith the viscous material, without requiring provision of an air-tighthousing for holding both the container and the syringe.

It is noted that the method according to this mode may be performed in amanner in which, after completing the container set by inserting theplunger into the container, the container set is placed and held inposition, or in a manner in which, after placing and holding only thecontainer in position, the container set is completed by inserting theplunger into the container held in position.

Similarly, this method may be also performed in a manner in which, aftercompleting the syringe set by inserting the first plug into the syringe,the syringe set is placed and held in position, or in a manner in which,after placing and holding only the syringe in position, the syringe setis completed by inserting the first plug into the syringe held inposition.

(2) The method according to mode (1), further comprising holding thecontainer set in an inverted orientation in which the first opening islocated below the second opening,

wherein the pushing is performed to downwardly push the plunger so as tomove the plunger towards the second opening of the container, to therebytransfer the viscous material from the container to the firstsub-chamber of the syringe, in an opposite direction to gravity, forfilling the syringe.

(3) The method according to mode (2), further comprising assisting inproducing upward displacement of the rod within the syringe such thatthe rod moves together with the first plug that moves upward as moreviscous material is filling the first sub-chamber, by applying an upwardforce to the rod.

(4) The method according to any one of modes (1)-(3), wherein thesyringe has an inner circumferential surface that has a circularcross-section and defines the syringe inner chamber,

the first plug is made by molding an elastically deformable material forforming a cup shape, to thereby provide the first plug with a silhouetteof a circle having an outer diameter substantially equal to an innerdiameter of the inner circumferential surface,

the first plug has a forward end portion and a rearward end portion,

the method further comprising inserting the first plug into the syringe,with the forward end portion located within the inner circumferentialsurface, and facing the third opening, and with the rearward end portionin contact with the inner circumferential surface.

(5) The method according to any one of modes (1)-(4), wherein the rod isa vacuum tube that can axially transmit a compressive force via thevacuum tube,

the vacuum tube is equipped with a second plug so as to extend throughthe second plug in a substantially air-tight manner, the second plugintroduced into the syringe,

the second plug, when placed within the syringe, separates the secondsub-chamber into a third sub-chamber nearer to the first plug, and afourth sub-chamber nearer to the fourth opening,

the second plug prevents both a first gas flow from the thirdsub-chamber towards the fourth sub-chamber and a second gas flow that isa reverse gas flow to the first gas flow, or only the second gas flow,

the vacuum tube, when placed within the syringe, is in fluidcommunication with the third sub-chamber, and

the inserting a rod is performed to introduce the vacuum tube and thesecond plug into the syringe, with the second plug in slidable contactwith the inner circumferential surface of the syringe,

the method further comprising withdrawing gas from the third sub-chambervia the vacuum tube, to thereby evacuate the third sub-chamber andtherefore the first sub-chamber.

According to this method, owing to the vacuum tube (e.g., which has itsnear end at which the vacuum tube is in communication with the firstsub-chamber, and its far end at which the vacuum tube is incommunication with a first vacuum source located outside), the thirdsub-chamber is evacuated, and subsequently, the third sub-chamber servesas a second vacuum source to evacuate the first sub-chamber because of agas flow via a radial clearance between the syringe and the first plug.

Because of this, a pressure differential is created between the firstsub-chamber and the third sub-chamber within the syringe, and the firstvacuum source in communication with the far end of the vacuum tube, suchthat the first sub-chamber and the third sub-chamber are higher inpressure than the first vacuum source. The pressure differential allowsgas flow from the first sub-chamber into the third sub-chamber via aradial clearance between the inner circumferential surface of thesyringe and the outer circumferential surface of the first plug, andeventually the gas is discharged to outside of the syringe via thevacuum tube. As a result, no gas is entrapped in the viscous materialwhile the viscous material is entering the first sub-chamber.

Consequently, according to this method, creation of a vacuum only in thesyringe prevents the viscous material held in the syringe fromcontacting gas, and therefore, no gas is entrapped in the viscousmaterial while the viscous material is entering the syringe, withoutrequiring provision of an air-tight housing for holding both thecontainer and the syringe.

Further, according to this method, because the first sub-chamber thatwill be filled with the viscous material is evacuated, in case gases areentrapped in the viscous material before the viscous material enters thesyringe, the viscous material will be also degassed, that is, the gasseswill be released from the viscous material while the viscous material isentering the syringe.

Still further, according to this method, a force is applied to the firstplug within the syringe by the vacuum tube in a direction such that,when the first plug is displaced by the force, the first plug movestowards the viscous material held in the syringe (i.e., a force actingfrom the fourth opening towards the third opening). The applied forcehas a direction that allows the first plug to be displaced whilereducing the volume of the first sub-chamber. In addition, theevacuation of the first sub-chamber also facilitates a reduction in thevolume of the first sub-chamber.

Therefore, according to this method, the application of the force by thevacuum tube and the creation of a vacuum within the first sub-chambertogether cooperate to facilitate gas release from the first sub-chambervia the radial clearance between the syringe and the first plug.

(6) The method according to mode (5), wherein the second plug hassubstantially the same shape as that of the first plug, and

the inserting a rod is performed to introduce the second plug into thesyringe, with the second plug and the first plug arranged in a serialarray in the same orientation.

(7) An apparatus of transferring a viscous material from a containerinto a syringe for filling the syringe,

wherein the container comprises:

a container housing;

a container inner chamber formed within the container housing forholding the viscous material; and

first and second openings formed in the container housing in fluidcommunication with the container inner chamber, and

the syringe comprises:

a syringe housing;

a syringe inner chamber formed within the syringe housing, into whichthe viscous material is to be transferred from the container for filingthe syringe; and

third and fourth openings formed in the syringe housing in fluidcommunication with the syringe inner chamber,

the apparatus further comprising:

a container set holder for holding a container set in position, thecontainer set provided by inserting a plunger into the container throughthe first opening, with the container holding the viscous material;

a syringe set holder for holding a syringe set with the third opening ofthe syringe removably coupled with the second opening of the containerin a substantially air-tight manner, the syringe set provided byinserting a first plug into the syringe in slidable contact with thesyringe, the first plug within the syringe separating the syringe innerchamber into a first sub-chamber nearer to the third opening, and asecond sub-chamber nearer to the fourth opening, the first plugpermitting gas flow in a direction from the first sub-chamber to thesecond sub-chamber, preventing viscous-material flow in the samedirection, and preventing gas and viscous-material flow in the reversedirection;

a rod located within the syringe so that the rod engages with the firstplug, to thereby apply a force to the first plug in a direction thatallows the first plug to move while reducing a volume of the firstsub-chamber; and

a pushing unit for pushing the plunger within the container so as tomove the plunger towards the second opening, to thereby extrude theviscous material from the container through the second opening, in orderto transfer the viscous material from the container into the firstsub-chamber of the syringe for filling the first sub-chamber.

(8) A method of holding in a container a viscous material to bedegassed, and turning the container under a vacuum using a mixer, tothereby agitate the viscous material while degassing the viscousmaterial, the method comprising:

setting a turning speed at which the mixer turns the container and alength of an agitating time during which the mixer continuously agitatesthe viscous material within the container, so as to minimize that sizesand/or number of voids finally remaining within the viscous material anda temperature rise of the viscous material caused by theagitating/degassing operation; and

simultaneously agitating and degassing the viscous material within thecontainer, by operating the mixer to orbit the container around anorbital axis and simultaneously rotating the container about arotational axis that is eccentric to the orbital axis, with thecontainer filled with the viscous material under a vacuum, so that theset values of the turning speed and the agitating time can be reached.

(9) A container set for containing a viscous material so that a desiredquantity of a dose of the viscous material can be dispensed, comprising:

a container having a longitudinal inner circumferential surface thatdefines a chamber for holding the viscous material; and

a plunger having a longitudinal outer circumferential surface that isaxially slidably fitted into the inner circumferential surface of thecontainer,

wherein the plunger has a tip end portion and abase end portion so as tobe coaxial with each other in a linear array, the plunger configured toallow the plunger to be inserted into the container, such that the tipend portion is first fitted into the inner circumferential surface ofthe container, and the base end portion is next fitted into the innercircumferential surface of the container.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cutaway cross-sectional front view illustrating aviscous-material filling device (hereinafter, referred to simply as“filling device”) that is suitable for use in performing aviscous-material filling method (hereinafter, referred to simply as“filling method”) according to a first embodiment of the invention.

FIG. 2 is a cutaway cross-sectional side view illustrating the fillingdevice depicted in FIG. 1.

FIG. 3 is an enlarged cutaway cross-sectional front view illustrating arelevant portion of the filling device depicted in FIG. 1, when in use.

FIGS. 4A, 4B and 4C are perspective views for explaining an exemplaryuse of a sealant, which is an exemplary viscous material that fills asyringe using the filling device depicted in FIG. 1.

FIG. 5 is an enlarged cutaway cross-sectional side view illustrating thecontainer set depicted in FIG. 3 that is constructed by inserting aplunger into a container.

FIG. 6 is an enlarged cross-sectional side view illustrating the syringedepicted in FIG. 3.

FIG. 7 is an enlarged cross-sectional side view illustrating the syringeset depicted in FIG. 3, which is constructed by inserting a first pluginto the syringe.

FIG. 8 is a cross-sectional side view illustrating the first plugdepicted in FIG. 7.

FIG. 9 is a cutaway cross-sectional side view illustrating the suctiontool depicted in FIG. 3.

FIG. 10 is a cutaway cross-sectional side illustrating the syringe setdepicted in FIG. 7, with the suction tool depicted in FIG. 9 inserted inthe syringe set.

FIG. 11 is a perspective view illustrating an assembly of the containerset, the syringe set and the suction tool, depicted in FIG. 3.

FIG. 12 is a process flowchart illustrating the filling method, alongwith a viscous-material preparation method performed prior to thefilling method.

FIG. 13 is a cutaway cross-sectional front view illustrating a relevantportion of a viscous-material filling device (hereinafter, referred tosimply as “filling device”), when in use, that is suitable for use inperforming a viscous-material filling method (hereinafter, referred tosimply as “filling method”) according to a second embodiment of theinvention.

FIG. 14 is a process flowchart illustrating the filling method accordingto the second embodiment, along with a viscous-material preparationmethod performed prior to the filling method.

FIG. 15 is a perspective view illustrating the container set, thesyringe set and the rod depicted in FIG. 13.

FIG. 16 is an exploded view illustrating a container set of aviscous-material filling device (hereinafter, referred to simply as“filling device”) that is suitable for use in performing aviscous-material filling method (hereinafter, referred to simply as“filling method”) according to a third embodiment of the invention.

EMBODIMENTS FOR CARRYING OUT THE INVENTION

Some of the more specific embodiments of the invention will be describedin the following in more detail with reference to the drawings.

FIG. 1 illustrates a viscous-material filling device (hereinafter,referred to simply as “filling device”) 10 in a cutaway cross-sectionalfront view, which is configured to be suitable for use in performing aviscous-material filling method (hereinafter, referred to simply as“filling method”) according to a first embodiment of the invention, andFIG. 2 illustrates the filling device 10 in a cutaway cross-sectionalside view. FIG. 3 illustrates a relevant portion of the filling device10, when in use, in an enlarged cutaway cross-sectional front view.

The filling method is performed to transfer a viscous material 14, whichis contained within a container 12, from the container 12 into, and tofill, a syringe 20 (i.e., a smaller container that divides the viscousmaterial 14 into smaller amounts, which is also referred to as“dispensing syringe”). The viscous material 14 in the container 12 isextruded from the container 12 by pushing a plunger 22 into thecontainer 12. The syringe 20 is filled with the extruded viscousmaterial 14 while under a vacuum. The viscous material 14 has aviscosity of, for example, about 1,100 Pas or about 11,100 poise.

An example of the viscous material 14 is a high-viscosity, electricallynon-conductive sealant; an example of the use of such a sealant is inaircrafts. For example, in aircrafts nowadays, a metal (or electricallyconductive) rivet 32 is inserted into a through bore 34 formed in thepanel 30 with a tapered section, as illustrated in FIG. 4A, and is thenupset, for the purpose of joining an electrically non-conductive panel30, which constitutes an outer panel thereof, to an inner frame (notshown).

Next, an electrically non-conductive sealant 40 is applied onto thesurface the head 36, as illustrated in FIG. 4B, so that the dish-shapedhead 36 of the upset rivet 32 is not exposed. At this time, a portion ofthe sealant 40 upwardly projects from the surface of the panel 30.

Then, the portion of the sealant 40 that upwardly projects from thesurface of the panel 30 is shaved off by an operator, as illustrated inFIG. 4C, to shape the surface of the sealant 40, and the surface of thesealant 40 is made flush with the surface of the panel 30. Thereafter,the surface of the panel 30 and the surface of the sealant 40 arepainted with the same paint.

An example of the syringe 20 is a cartridge that is removably attachedto a dispenser gun (not shown). An example of such a dispenser gun isdisclosed in U.S. Pat. No. 7,690,530, the content of which isincorporated herein by reference in its entirety.

Once the cartridge (i.e. the syringe 20), which has been filled with theviscous material 14, has been loaded into the dispenser gun, the viscousmaterial 14 is dispensed by the dispenser gun from the cartridge in therequired amount and is applied to a target object (e.g., theabove-mentioned rivet 32). In other words, in the present embodiment,the syringe 20 and a below-described first plug are used to both filland apply the viscous material 14.

In FIG. 5, the container 12 is illustrated in a cross-sectional sideview. In the present embodiment, the same container 12 is used for theproduction of the viscous material 14 (two-component mixing, asdescribed below), the degassing of the viscous material 14 (centrifugalvacuum degassing using a mixer, as described below) after the productionthereof, and the storage and transportation of the viscous material 14prior to filling into the syringe 20.

As illustrated in FIG. 5, the container 12 has alongitudinally-extending hollow housing 50 (an example of theaforementioned container housing) and a cylindrical chamber 52 (anexample of the aforementioned container inner chamber) that is formedcoaxially within the housing 50. The chamber 52 has an opening 54 (anexample of the aforementioned first opening) and a base portion 56. Thebase portion 56 has a recess that forms a generally hemispherical shape.Because the base portion 56 has a continuous shape, the viscous material14 flows in the chamber 52 more smoothly than if the base portion 56 hada flat shape; as a result, the mixing efficiency of the viscous material14 is improved. An example of a material constituting the container 12is POM (polyacetal); another example is Teflon (registered trademark),although these are not limiting.

In the base portion 56 of the chamber 52, a discharge passage 57 (anexample of the aforementioned second opening) is formed for dischargingthe viscous material 14 (a mixture of Solutions A and B), which iscontained within the chamber 52, into the syringe 20; the dischargepassage 57 is selectively closed by a removable plug (not shown).

As illustrated in FIG. 5, the plunger 22 is pushed into the chamber 52of the container 12 in order to discharge the viscous material 14 fromthe container 12. The plunger 22 has a main body portion 58 and anengagement portion 59 formed at the rear end of the main body portion58. The main body portion 58 has an exterior shape that is complementaryto the interior shape of the chamber 52 of the container 12 (e.g., anexterior shape having a protrusion that forms a generally hemisphericalshape). The engagement portion 59 is smaller in diameter than the mainbody portion 58; when an external force is loaded by the filling device10, the plunger 22 advances. As the plunger 22 moves within the chamber52 closer to the discharge passage 57, viscous material 14 is extrudedfrom the discharge passage 57.

In FIG. 6, the syringe 20 is illustrated in a cross-sectional side view.The syringe 20 has a coaxial, cylindrical main body portion 60, whichextends longitudinally with a uniform cross section, and a hollow baseportion 62, which is connected at one of its two ends with the main bodyportion 60. The base portion 62 has a tubular portion 64 (an example ofthe aforementioned third opening) at its tip end, which is smaller indiameter than the main body portion 60; on the other side that connectswith the main body portion 60, the base portion 62 has a taperingtapered portion 66. The opposite end of the main body portion 60 has anopening 96 (an example of the aforementioned fourth opening). An exampleof a material constituting the syringe 20 is POM (polyacetal), but thisis not limiting.

In the present embodiment, the viscous material 14 is filled from thecontainer 12 into the syringe 20 by passing through the tubular portion64 located at one of the two ends of syringe 20; after completion of thefilling, to dispense the viscous material 14 for use, the viscousmaterial 14 is discharged from the syringe 20 by passing through thesame passage, i.e. the tubular portion 64 (the smallest diameter passageof the syringe 20). In other words, the flow of the viscous material 14into and out of the syringe 20 is carried out by passing through thesame smallest-diameter passage.

In the present embodiment, while transferring the viscous material 14from the container 12 to the syringe 20, the container 12 is held inspace, as illustrated in FIG. 5, such that the container 12 is orientedwith the opening 54 of the chamber 52 facing downward and the dischargepassage 57 of the base portion 56 facing upward (upside-down position).In this state, the plunger 22 is moved upwardly within the chamber 52.As a result, the viscous material 14 is upwardly extruded from thechamber 52.

Furthermore, while transferring the viscous material 14 from thecontainer 12 to the syringe 20, the syringe 20 is held in space with theopening 68 facing upward and with the base portion 62 facing downward.In this state, when the viscous material 14 is upwardly extruded fromthe container 12, it is injected via the base portion 62 of the syringe20.

As a result, the viscous material 14 increasingly accumulates in thesyringe 20 via the base portion 62 (lower portion), such that theuppermost level of the viscous material 14 rises in the direction fromthe base portion 62 to the opening 68 (upper portion).

Thus, in the present embodiment, when the viscous material 14 isinjected into the syringe 20 by injecting via the lower portion of thesyringe 20, the new viscous material 14 does not splash onto thepreviously accumulated portion, unlike the case of injecting via theupper portion, in which the new viscous material 14 drops due to itsweight. As a result, when the viscous material 14 is injected into thesyringe 20, it is less likely that voids will form in the viscousmaterial 14 accumulated in the syringe 20, than if the viscous material14 were to be injected via the upper portion of the syringe 20.

As illustrated in FIGS. 1 and 2, the filling device 10 has a containerholder mechanism 70 (an example of the aforementioned container setholder) at its lower portion that removably holds the container 12; onthe other side, the filling device 10 has a syringe holder mechanism 72(an example of the aforementioned syringe set holder) at its upperportion that removably holds the syringe 20.

The container holder mechanism 70 has a base plate 80, which sits on theground, a top plate 82, which is not vertically movable and is locatedabove the base plate 80, and a plurality of vertical parallel shafts 84,each of which is fixedly secured at its two ends to the base plate 80and the top plate 82 (in the present embodiment, two shafts disposedsymmetrically relative to a vertical centerline of the container holdermechanism 70). The top plate 82 has a through hole 90. The through hole90 is coaxial with the vertical centerline of the container holdermechanism 70.

A guide plate 92 is fixedly secured to a lower face of the top plate 82.The guide plate 92 has a guide hole 94 coaxial with the through hole 90.The guide hole 94 penetrates through the guide plate 92 in the thicknessdirection with a uniform cross-section. The guide hole 94, asillustrated in FIG. 3, has an inner diameter that is slightly largerthan the outer diameter of the base portion 56 of the container 12, andit is possible to fit the container 12 within the guide hole 94 withoutany noticeable play. Due to the guide hole 94, the container 12 isaligned relative to the top plate 82 in the horizontal direction (theradial direction of the container 12).

As illustrated in FIG. 3, when the base portion 56 of the container 12is in the state that it is fitted in the guide hole 94, the container 12abuts on the lower surface of the top plate 82 at a tip end surface ofthe base portion 56 (in the same plane). As a result, the container 12can be aligned relative to the top plate 82 in the vertical direction(the axial direction of the container 12).

As illustrated in FIGS. 1 and 2, the container holder mechanism 70further has a vertically movable plate 100. The movable plate 100 has aplurality of sleeves 102, into which the shafts 82 are axially slidablyfitted. By manipulating a lock mechanism 104, the operator can move themovable plate 100 and stop the movement in any position in the verticaldirection.

The movable plate 100 has a stepped positioning hole 106 coaxial withthe guide hole 94. The positioning hole 106 penetrates through themovable plate 100 in the thickness direction. The positioning hole 106has a larger-diameter hole 110 on the side closer to the guide hole 94,a smaller-diameter hole 112 on the opposite side, and a shoulder surface114 between the larger-diameter hole 110 and the smaller-diameter hole112 and facing towards the guide hole 94.

The larger-diameter hole 110 has an inner diameter that is slightlylarger than the outer diameter of the opening 54 of the container 12 andthe container 12 is aligned relative to the movable plate 100 (andtherefore the top plate 102) in the horizontal direction (the radialdirection of the container 12).

The tip end surface of the opening 54 of the container 12 (in the sameflat plane) abuts on the shoulder face 114, and the container 12 isaligned relative to the movable plate 100 (therefore the top plate 102)in the vertical direction (the axial direction of the container 12).

The smaller-diameter hole 112 has an inner diameter that is slightlylarger than the outer diameter of the plunger 22, and the plunger 22 isslidably fitted into the smaller-diameter hole 112. The smaller-diameterhole 112 serves as a guide hole for guiding axial movement of theplunger 22.

A container set is constructed by inserting the plunger 22 into thecontainer 12, and the container set is attached to the top plate 82,with the movable plate 100 sufficiently spaced from the top plate 82 inthe downward direction. Thereafter, the movable plate 100 is upwardlymoved until the tip end face of the opening 54 of the container 12 abutson the shoulder face 114. At this position, the movable plate 100 isfixedly secured to the shafts 84. As a result, the retention of thecontainer set on the container holder mechanism 70 is completed.

As illustrated in FIGS. 1 and 2, the container holder mechanism 70further has an air cylinder 120 (an example of the aforementionedpushing unit) serving as an actuator and coaxial with the guide hole 94.A rod 122, which serves as a vertically movable member, upwardlyprojects from the air cylinder 120, and a pusher 124 is affixed at thetip end of the rod 122. The pusher 124, as illustrated in FIG. 3,engages with the engagement portion 59 of the plunger 22 of thecontainer set that is held in the container holder mechanism 70. In theengagement position, as the pusher 124 advances, the plunger 22 advancesrelative to the container 12 so as to reduce the volume of the chamber52.

The air cylinder 120 is double-acting and, based on the operator′actions, the piston 124 thereof selectively advances from an initialposition to an active position (upward movement by pressurization),retreats from the active position to an inactive position (downwardmovement by pressurization), and stops at any desired position (fromboth gas chambers within the air cylinder 120). Although notillustrated, the air cylinder 120 is connected to a high-pressure source(its primary pressure is, e.g., 0.2 MPa) via a hydraulic pressurecontrol unit having flow control valve(s).

As illustrated in FIG. 2, the container holder mechanism 70 further hasa gas spring 126 serving as a damper. The gas spring 126 extendsvertically and is pivotably coupled at its two ends with the base plate80 and the movable plate 100, respectively. The gas spring 126 isprovided to restrict the downward movement of the movable frame 100 dueto gravity when the lock mechanism 104 is in an unlocked position.

As illustrated in FIGS. 1 and 2, the syringe holder mechanism 72 isequipped with abase frame 130 that is fixedly secured to the top plate82, an air cylinder 132 serving as an actuator, a top frame 134 and amovable frame 136.

The air cylinder 132 has a vertically-extending main body 140, which isfixedly secured to the top plate 82 and the top frame 134, and avertically-moving rod 142 that is linearly movable relative to the mainbody 140. The upper end of the vertically-moving rod 142 (the end of thevertically-moving rod 142 that projects from the main body 140) isfixedly secured to the movable frame 136.

The air cylinder 132 is double acting, and based on operator's actions,the vertically-moving rod 142 thereof selectively advances from aninitial position to an active position (upward movement bypressurization), retreats from the active position to an inactiveposition (downward movement by pressurization), and floats at anydesired position (permitting exhaust from both gas chambers in the aircylinder 132). That is, the air cylinder 132 can selectively switchbetween an advanced mode, a retracted mode and a floating mode. Althoughnot illustrated, the air cylinder 132 is connected to a high pressuresource via a hydraulic pressure control unit.

A plurality of sleeves 144 (in the present embodiment, two parallelsleeves disposed symmetrically with the air cylinder 132 interposedtherebetween) are fixedly secured to the main body 140. A plurality ofvertically-extending shafts 146 are slidably fitted into the respectivesleeves 144. The upper end portion of each shaft 146 is fixedly securedto the movable frame 136.

Each of the base frame 130, the top frame 134, the main body 140 and thesleeves 144 is a stationary member in the syringe holder mechanism 72,while the movable frame 136, the vertically-movable member 142, and theshafts 146 are each movable members that vertically move in unison.

As illustrated in FIG. 2, the syringe holder mechanism 72 is furtherequipped with a gas spring 150 serving as a damper. The gas spring 150extends vertically between the base frame 130 and the movable frame 136.The gas spring 150 is equipped with a cylinder 152 having a gas chamber(not shown), and a rod 154 that is extendable and retractable relativeto the cylinder 152. At one end thereof, it is pivotably coupled to thebase frame 130.

A tip end of the rod 154 detachably engages a lower surface of themovable frame 136. As a result, although the movable frame 136 cancompress the rod 154, it cannot extend the rod 154. When in a compressedstate, the rod 154 applies an upward force against the movable frame136, which assists the upward movement of the movable frame 136.

As illustrated in FIG. 7, the un-filled syringe 20 is held by thesyringe holder mechanism 72 with a first plug 160 inserted in thesyringe 20. As illustrated in FIG. 8, the first plug 160 is made bymolding an elastically deformable material (e.g., PP) into a cup shape.The first plug 160 has a silhouette of a circle having an outer diameterthat is substantially equal to an inner diameter of the innercircumferential surface 162 (see FIG. 7) of the syringe 20.

The first plug 160 has an anterior end portion 164 and a posterior endportion 166. The first plug 160 is inserted into the syringe 20, withthe anterior end portion 164 facing towards the base portion 62 of thesyringe 20, and with the posterior end portion 166 contacting the innercircumferential surface 162 of the syringe 20. A syringe set is providedby inserting the first plug 160 into the syringe 20. By inserting thefirst plug 160 into the syringe 20 in the proximity of the base portion62, a chamber within the syringe 20 is divided into a first sub-chamber170, which is closer to the base portion 62, and a second sub-chamber172, which is closer to the opening 68.

The first plug 160, when inserted in the syringe 20, provides anon-return function for gas (typically, air).

More specifically, within the syringe 20, when the first sub-chamber 170is at a higher air pressure than the second sub-chamber 172, air flow ispermitted from the first sub-chamber 170 to the second sub-chamber 172via a clearance existing between the inner circumferential surface 162and an outer circumferential surface of the first plug 160. In contrast,when the first sub-chamber 170 is at a lower air pressure than thesecond sub-chamber 172, this pressure differential causes the innercircumferential surface 162 of the syringe 20 and the outercircumferential surface of the first plug 160 to be brought intoair-tight contact with each other, resulting in the blockage of air flowfrom the second sub-chamber 172 to the first sub-chamber 170.

Therefore, due to the non-return function provided by the first plug160, the creation of a vacuum in the second sub-chamber 172 leads to thecreation of a vacuum in the first sub-chamber 170; thereafter, even ifthe pressure of the second sub-chamber 172 returns to atmosphericpressure, the first sub-chamber 170 is maintained at a vacuum.

In addition, the first plug 160 provides a large resistance to the flowof viscous material 14 through the clearance between the innercircumferential surface 162 and the outer circumferential surface of thefirst plug 160, due to the viscosity of the viscous material 14. As aresult, the flow of viscous material 14 from the first sub-chamber 170to the second sub-chamber 172 is either completely blocked, or even ifnot completely blocked, then effectively blocked. In addition, the flowof viscous material 14 from the second sub-chamber 172 to the firstsub-chamber 170 is completely blocked. Therefore, due to the first plug160, the viscous material 14 can be stored in the first sub-chamber 170without leakage of the viscous material 14 to the second sub-chamber172.

In the present embodiment, after the viscous material 14 has been filledinto the syringe 20, the first plug 160 provides the function ofpreventing leakage of the viscous material 14 from the syringe 20.Incidentally, the syringe 20 that has been filled with the viscousmaterial 14 is then loaded into the aforementioned dispenser gun as theaforementioned cartridge. When a trigger is pulled by the operator, thedispenser gun dispenses the viscous material 14 from the aforementionedcartridge, only in the necessary amount for the sealant, by pushing outthe first plug 160. Therefore, after the syringe 20 has been loaded intothe dispenser gun, the first plug 160 functions as a plunger that pushesout the viscous material 14.

As illustrated in FIG. 3, although the base portion 62 of the syringe 20is directly coupled to the base portion 56 of the container 12 in thepresent embodiment, such direct coupling is not essential to practicethe invention; for example, they also may be indirectly coupled via anadaptor. In addition, in another embodiment, a plurality of parallelsyringes 20 are connected to one container 12 via a common adaptor.

In the present embodiment, the container 12 and the syringe 20 aredirectly coupled together, e.g., by screwing together male and femalethreads, with the container 12 retained in the filling device 10, andthe syringe 20 is aligned relative to the container 12 in both of theradial direction and the axial direction.

As illustrated in FIG. 3, a suction tool 180 is inserted into thesyringe 20, with the aforementioned container set held by the containerholder mechanism 70, and with the aforementioned syringe set coupled tothe container set.

The suction tool 180 is held by the syringe holder mechanism 72. In thepresent embodiment, the syringe holder mechanism 72 holds the suctiontool 180 and the suction tool 180 is, in turn, inserted into the syringe20; consequently, the syringe 20 is held by the syringe holder mechanism72.

In FIG. 9, the suction tool 180 is illustrated in a cutawaycross-sectional side view. The suction tool 180 has a vacuum tube 182,which extends linearly and is rigid, and a second plug 190, which isfixedly secured to the tip end of the vacuum tube 182. The vacuum tube182 is a steel pipe (can be replaced with a plastic pipe), and servesnot only as a conduit for a flow of air to an external vacuum source(not shown), but also as a rod capable of transmitting compressiveforces in the axial direction. In FIG. 10, the suction tool 180 isillustrated while being installed in the syringe 20.

The second plug 190 has substantially the same shape and materialcomposition as the first plug 160 depicted in FIG. 8. As illustrated inFIG. 10, the second plug 190 is inserted into the syringe 20, with thesecond plug 190 disposed in series with the first plug 160, which waspreviously placed in the syringe 20, and with the second plug 190 in thesame orientation as the first plug 160. Due to the insertion of thesecond plug 190, the second sub-chamber 172 within the syringe 20 isdivided into a third sub-chamber 200, which is closer to the first plug160, and a fourth sub-chamber 202, which is closer to the opening 68.

Similar to the first plug 160, the second plug 190 provides a non-returnfunction for gas (typically, air) when inserted into the syringe 20.

More specifically, within the syringe 20, when the third sub-chamber 200is at a higher air pressure than the fourth sub-chamber 202, air flow ispermitted from the first sub-chamber 170 to the fourth sub-chamber 202via the radial clearance existing between the inner circumferentialsurface 162 and an outer circumferential surface of the second plug 190.In contrast, when the third sub-chamber 200 is at a lower air pressurethan the fourth sub-chamber 202, the pressure differential causes theinner circumferential surface 162 of the syringe 20 and the outercircumferential surface of the second plug 190 to be brought intoair-tight contact with each other, resulting in the blockage of air flowfrom the fourth sub-chamber 202 to the third sub-chamber 200.

Therefore, the non-return function provided by the second plug 190enables the third sub-chamber 200 to be subjected to a sub-atmosphericpressure, while the fourth sub-chamber 202 is subjected to anatmospheric pressure.

As illustrated in FIG. 9, the vacuum tube 182 has an anterior endportion 210 and a trailing end portion 212. The vacuum tube 182 isconnected to the aforementioned hydraulic pressure control unit at thetrailing end portion 212 via a flexible hose (not shown), and is furtherconnected to the aforementioned vacuum source (having an exemplarypressure that is about 0.1 MPa lower than an atmospheric pressure of0.101325 MPa, or that is stronger) via the hydraulic pressure controlunit. The vacuum source, together with the hydraulic pressure controlunit, constitutes an example of the device for creating a vacuum.

The second plug 190 is fixedly secured to the anterior end portion 210at a position slightly spaced away from a tip end surface of theanterior end portion 210. The vacuum tube 182 coaxially extends throughthe second plug 190 in a substantially air-tight contact with the secondplug 190. The tip end surface of the anterior end portion 210 is closedin an air-tight manner by a stop 214. As illustrated in FIG. 10, theanterior end portion 210 abuts, via a tip end surface of the stop 214,on an inner face of an interior surface of the anterior end portion 164of the first plug 160, which sets a definite approaching limit of thesecond plug 190 relative to the first plug 160 (i.e., the smallestpossible distance between the first plug 160 and the second plug 190).

As illustrated in FIG. 9, a suction hole 216, which radially penetratesthrough the anterior end portion 210, is formed at a position that isnot obstructed by the stop 214. The suction hole 216 is ultimatelyconnected with the aforementioned vacuum source via an inner passage 218of the vacuum tube 182. As illustrated in FIG. 10, the suction hole 216is in fluid communication with the third sub-chamber 200 when the stop214 is in abutment with the first plug 160, which enables the suctiontool 180 to create a vacuum within the third sub-chamber 200 or toevacuate the third sub-chamber 200, while the fourth sub-chamber 202 ismaintained at atmospheric pressure.

As illustrated in FIG. 11, when the third sub-chamber 200 is evacuated,air leaks from the first sub-chamber 170 to the third sub-chamber 200via the radial clearance between the syringe 20 and the first plug 160,and the leaked air is, in turn, suctioned by the vacuum source via thevacuum tube 182. This causes the first sub-chamber 170 to be evacuated.At this time, the fourth sub-chamber 202 is maintained at atmosphericpressure.

As illustrated in FIG. 11, by pushing the plunger 22 into the container12, viscous material 14 is extruded from the container 12 via the baseportion 56, and the extruded viscous material 14 fills the firstsub-chamber 170 under a vacuum. As the volume of viscous material 14filling the first sub-chamber 170 increases, the first plug 160 isfurther displaced by the viscous material 14 and moves upwardly relativeto the syringe 20. Therefore, the suction tool 180 moves upwardlyrelative to the syringe 20.

As illustrated in FIGS. 1 and 2, the vacuum tube 182 is fixedly securedto the movable frame 136. The vacuum tube 182 extends coaxially with thevertical centerline of the filling device 10 (coaxial with thecenterline of the guide hole 94). The second plug 190 is fixedly securedto the vacuum tube 182, and the second plug 190 is inserted into thesyringe 20 without play. As a result, the syringe 20 is aligned relativeto the top plate 82.

Next, the filling method will be described in more detail with referenceto the process flowchart depicted in FIG. 12, which is followed bydescription of how to prepare the viscous material 14.

The viscous material 14 is a high-viscosity synthetic resin, andexhibits thermosetting properties, such that the viscous material 14cures when heated above a prescribed temperature (e.g., 50° C.); oncecured, the original properties of the viscous material 14 will not berestored even if the temperature decreases. In addition, the viscousmaterial 14 also exhibits the property that, when the viscous material14 is cooled below a prescribed temperature (e.g., −20° C.) prior tocuring and is frozen, the chemical reaction (curing) in the viscousmaterial 14 stops. Thereafter, when the viscous material 14 is heatedand thawed, the chemical reaction (curing) in the viscous material 14restarts.

In the present embodiment, the viscous material 14 is a two-part typethat is furnished by mixing two solutions, which are “Solution A”(curing agent) and “Solution B” (major component). An example of“Solution A” is PR-1776 B-2, Part A (i.e., an accelerator component, anda manganese dioxide dispersion) of PRC-DeSoto International, U.S.A., andan example of “Solution B,” which is combined with Solution A, isPR-1776 B-2, Part B (i.e., a base component, and a filled modifiedpolysulfide resin) of PRC-DeSoto International, U.S.A.

Therefore, as illustrated in FIG. 12, in order to produce the viscousmaterial 14, the two parts are first mixed in the container 12 in stepS11. Next, in step S12, agitating and degassing are performed on theviscous material 14 held in the container 12 using a mixer (not shown).In the present embodiment, the same container 12 is used to mix the twoparts for the production of the viscous material 14, and to agitatingand degas the viscous material 14 using the mixer.

An example of such a mixer is disclosed in Japanese Patent ApplicationPublication No. HEI 11-104404, the content of which is incorporatedherein by reference in its entirety. In the present embodiment, such amixer is used to orbit the container 12 around an orbital axis andsimultaneously rotate the container 12 about a rotational axis that iseccentric to the orbital axis, with the container 12 filled with theviscous material 14 under a vacuum, so that the viscous material 14 canbe simultaneously agitated and degassed within the container 12.

The viscous material 14 within the mixer is agitated due to thecentrifugal force created by the planetary motion produced by the mixer.Further, air bubbles trapped in the viscous material 14 are releasedfrom the viscous material 14, due to the synergistic effect of thecentrifugal force generated by the planetary motion of the mixer and thenegative pressure caused by the vacuum atmosphere; as a result, theviscous material 14 is degassed. This completely or adequately preventsgeneration of voids within the viscous material 14.

In this agitating/degassing process, the rotating speed and thecontinuous agitating time of the container 12 by the mixer are set so asto minimize as much as possible both the sizes and/or number of voidsthat ultimately exist within the viscous material 14 and the amount thatthe temperature of the viscous material 14 increases due to theagitating/degassing operation. The faster the rotating speed and thelonger the continuous agitating time, the greater is the amount that thevoid formation is suppressed, but the starting time of the curing of theviscous material 14 caused by the higher temperatures due to the jouleheating is easily sped up. Thus, for the viscous material 14, there is arelationship of the tradeoffs between the void conditions and thetemperature conditions. Therefore, in the present embodiment, therotating speed and the continuous agitating time are set so that thevoid conditions and the temperature conditions can be both maximized.

After the viscous material 14 has been mixed and agitated/degassedwithin the container 12 in the manner described above, an operation thattransfers and fills the viscous material 14 from the container 12 intothe syringe 20 starts as illustrated in FIG. 12.

In step S21, the operator first inserts the plunger 20 into thecontainer 12 that has been filled with the viscous material 14, asillustrated in FIG. 5, to thereby prepare the container set. In stepS22, the operator next attaches the container set to the containerholder mechanism 70 of the filling device 10 with the container setinverted, as illustrated in FIG. 3, to thereby retain the container setin the filling device 10.

More specifically, prior to the retention of the container set in thecontainer holder mechanism 70, the movable plate 100 is retreateddownwardly from the container set. The operator first puts the containerset on the retreated movable plate 100 at a prescribed position and inan inverted orientation. Thereafter, the operator raises the movableplate 100 together with the container set until the container 12 abutson the top plate 82. Lastly, the operator fixes the movable plate 100 atthat position.

Subsequently, in step S23, the operator inserts the first plug 160 intothe syringe 20 as illustrated in FIG. 7, to thereby prepare the syringeset. Thereafter, in step S24, the syringe set is coupled to thecontainer set, which was previously retained by the filling device 10 inan inverted orientation, in a substantially air-tight manner, asillustrated in FIG. 3, to thereby retaining the syringe set in thefilling device 10.

Prior to the attachment of the syringe set to the filling device 10, theair cylinder 130 is placed in the aforementioned advanced mode, in whichthe vertically-movable rod 142 pushed out; as a result, the suction tool180 is in a position that is upwardly retreated from the syringe 20. Inother words, the suction tool 180 does not obstruct the attachment ofthe syringe set to the filling device 10.

Subsequently, in step S25, the air cylinder 132 is switched to theaforementioned retracted mode to retract the vertically movable rod 142and to thereby insert the retreated suction tool 180 into the syringe20. The suction tool 180, which includes the vacuum tube 182 and thesecond plug 190, is downwardly moved by the air cylinder 132 until thestop 214 of the vacuum tube 182 abuts on the first plug 160, which waspreviously put into the syringe 20.

Thus, as illustrated in FIG. 3, the first plug 160 and the second plug190 will be positioned within the syringe 20 in series with each other,with the first plug 160 located below and the second plug 190 locatedabove. An advancing limit of the first plug 160 is defined by abuttingon a tip end portion of a portion, which forms the discharge passage 57,within the base portion 56 of the container 12.

Thereafter, the air cylinder 132 is switched to the aforementionedfloating mode; as a result, if the assistance by the gas spring 150 isdisregarded, the force acting on the first plug 160 from the vacuum tube182 has a value equal to the summation of the weight of the vacuum tube182 and the weight of member(s), which move together with the vacuumtube 182, minus the value of the sliding resistance. This force is aforce that urges the first plug 160 in the direction towards the baseportion 62 of the syringe 20, and is a force that reduces the volume ofthe first sub-chamber 170.

Thereafter, in step S26, the vacuum source suctions air from the thirdsub-chamber 200 via the vacuum tube 182, to thereby evacuate the thirdsub-chamber 200, as illustrated in FIG. 11. The first sub-chamber 170 isalso evacuated thereby. Although the viscous material 14 will bedispensed from the container 12 into the first sub-chamber 170 afterthis, prior thereto, there is substantially no air in the firstsub-chamber 170 that would cause voids to exist within the viscousmaterial 14.

As is apparent from the above description, according to the presentembodiment, the third sub-chamber 200 within the syringe 20 is evacuatedby the vacuum tube 182, and then with the third sub-chamber 200 actingas a second vacuum source, the first sub-chamber 170 is evacuated due tothe air flow via the radial clearance between the inner circumferentialsurface of the syringe 20 and the outer circumferential surface of thefirst plug 160.

As a result, a pressure differential is generated by the firstsub-chamber 170 and the third sub-chamber 200 within the syringe 20,which are at a higher pressure than the aforementioned external vacuumsource that is connected at the distal end of the vacuum tube 182. Dueto this pressure differential, air present in the first sub-chamber 170flows into the third sub-chamber 200 via the radial clearance betweenthe inner circumferential surface 162 of the syringe 20 and the outercircumferential surface of the first plug 160; consequently, the air isdischarged to outside of the syringe 20 via the vacuum tube 182. As aresult, during the filling of the viscous material 14 into the firstsub-chamber 170, air is not incorporated into the viscous material 14.

Consequently, according to the present embodiment, once the space withinthe syringe 20 is evacuated, in order to prevent incorporation of airinto the viscous material flowing into the syringe 20, it is notnecessary to provide an air-tight housing for holding both the container12 and the syringe 20 in order to prevent air from being introduced intothe viscous material 14 while the viscous material 14 is entering thesyringe 20.

Therefore, according to the present embodiment, it is not necessary toprovide a housing for holding the entirety of the container 12 and thesyringe 20 in an air-tight manner and it is not necessary to evacuatesuch a housing in order to prevent air from being incorporated into theviscous material 14 during the filling process.

As a result, according to the present embodiment, for preventing airfrom being incorporated into the viscous material 14 during the fillingprocess, the trend of increasing the part count and the trend ofincreasing the size of the filling device 10 are reduced; consequently,the trend of increasing the weight and cost is reduced.

Further, according to the present embodiment, the filling of the viscousmaterial 14 can be performed using the filling device 10 even in a workenvironment in which only a confined workspace is available; moreover,the maximum number of the containers 12 and the syringes 20 that canpossibly occupy the same workspace at the same time can be easilyincreased.

Still further, according to the present embodiment, because the firstsub-chamber 170 that will be filled with the viscous material 14 isevacuated, in case air is entrapped in the viscous material 14 beforethe filling, it will be degassed during the filling, i.e. it is possibleto extract from the viscous material 14 any air that has beenincorporated therein at the same time.

Still further, according to the present embodiment, a force (i.e. aforce acting in the direction from the opening 68 towards the firstsub-chamber 170) is applied to the first plug 170 within the syringe 20by the weight of the vacuum tube 182 in the direction moves it towardsthe viscous material 14 that has flowed into the syringe 20. Thedirection of the applied force is the direction that reduces the volumeof the first sub-chamber 170. In addition, the evacuation of the firstsub-chamber 170 also facilitates the reduction in the volume of thefirst sub-chamber 170.

Therefore, according to the present embodiment, air that is present inthe first sub-chamber 170 is caused to be evacuated through the radialclearance between the syringe 20 and the first plug 160 by thecooperative action of the application of the force by the vacuum tube182 and the evacuation of the first sub-chamber 170.

Still further, according to the present embodiment, a force is appliedto the first plug 160 within the syringe 20 by the weight of the vacuumtube 182 in the direction that moves it towards the viscous material 14that has flowed in the syringe 20. The direction of the applied force isthe direction that reduces the volume of the first sub-chamber 170. Inaddition, the evacuation of the first sub-chamber 170 also facilitatesthe reduction in the volume of the first sub-chamber 170.

Therefore, according to the present embodiment, air that is present inthe first sub-chamber 170 is caused to be evacuated through the radialclearance between the syringe 20 and the first plug 160 by thecooperative action of the application of the force by the vacuum tube182 and the evacuation of the first sub-chamber 170.

Subsequently, in step S27, by the air cylinder 120 extending the rod 122as illustrated in FIG. 1, the pusher 124 first engages with theengagement portion 59 of the plunger 22 from the rear side thereof, asillustrated in FIG. 3. Thereafter, when the air cylinder 120 furtherextends the rod 122, the plunger 22 rises and is pushed into thecontainer 12. With this, the viscous material 14 is extruded from thecontainer 12 against the force of gravity, to thereby initiate thefilling of the first sub-chamber 170.

Thereafter, the entire first sub-chamber 170, which is in the initialstate depicted in FIGS. 3 and 7, is filled with the viscous material 14.Subsequently, as the filling of the viscous material 14 continues, thevolume of the first sub-chamber 170 increases and the first plug 160,the second plug 190, the vacuum tube 82 and the movable frame 136 rise.At his time, the viscous material 14 within the first sub-chamber 170 isprevented from leaking into the third sub-chamber 200 by the cooperativeaction of its viscosity and the miniscule radial clearance between theinner circumferential surface 162 of the syringe 20 and the outercircumferential surface of the first plug 160.

Prior to the filling of the viscous material 14 into the syringe 20, thegas spring 150 depicted in FIG. 2 is in a compressed state due to themovable frame 136. In response thereto, the gas spring 150 applies aforce to the movable frame 136 that lifts the movable frame 136 togetherwith the suction tool 180.

The downward force due to the weight of the movable frame 136 and thesuction tool 180 does not exceed the lifting force exerted onto themovable frame 136 and the suction tool 180 by the gas spring 150. Due tothis, the downward force of the movable frame 136 and the suction tool180 is partially offset by the gas spring 150; as a result, the downwardforce of the movable frame 136 and the suction tool 180 is less than ifthe gas spring 150 were not present and it is easier to rise.

Therefore, after the entire first sub-chamber 170, which is in theinitial state depicted in FIGS. 3 and 7, is filled with the viscousmaterial 14, and when the volume of the first sub-chamber 170 furtherincreases, it is thereby possible to raise the first plug 160, thesuction tool 180 (including the second plug 190 and the vacuum tube 182)and the movable frame 136 without increasing much the pressure of theviscous material 14 within the first sub-chamber 170. In other words, inthe present embodiment, the lifting of the suction tool 180 (includingthe second plug 190 and the vacuum tube 182) and the movable frame 136in step S28 is mechanically assisted by the gas spring 152.

Thereafter, when the plunger 22 advances up to the advancing limit andbottoms out in the container 12, by the air cylinder 132 extending thevertically movable rod 142 in step S29, the suction tool 180 is liftedwith the first plug 160 remaining as is in the syringe 20, and thesuction tool 180 is retracted from the syringe 20.

Subsequently, in step S30, the syringe set is removed from the container12 and the filling device 10. Thereafter, in step S31, the container setis removed from the filling device 10. Then, the transferring andfilling of the viscous material 14 from the one container 12 to the onesyringe 20 is completed.

Next, a second embodiment of the present invention will be described.The present embodiment, however, is similar to the first embodiment inmany elements; therefore, the present embodiment will be described indetail with regard to only the elements that differ from those of thefirst embodiment, while a redundant description of the elements commonwith those of the first embodiment will be omitted by using the samereference numerals.

In the first embodiment, the second plug 190 in addition to the firstplug 160 is inserted into the syringe 20, and the vacuum tube 182 isengaged with the first plug 160, whereby the first sub-chamber 170 isevacuated.

In contrast thereto, in the present embodiment as compared to the firstembodiment, the second plug 190 is omitted, and as illustrated in FIG.13, a simple rod 230 that is not connected with the aforementionedvacuum source engages with the first plug 160, so that the rod 230 onlyfunctions to urge the first plug 160 towards the base portion 62 of thesyringe 20, without evacuating the first sub-chamber 170. The basicstructure of the rod 230 is similar to the vacuum rod 182 depicted inFIG. 9, except for elements associated with the second plug 190.

However, the rod 230 is held by the filling device 10 in a similarmanner to the vacuum tube 182. More specifically, the rod 230 is movedupward and downward by the air cylinder 132, and a lifting force isexerted thereon by the gas spring 152. The rod 230, in the presentembodiment, is comprised of a steel pipe, similar to the vacuum tube182, so that the rod 230 can have the required rigidity (fortransmitting a compressive force in the axial direction) with a reducedweight. Alternatively, the rod 230 may be a plastic pipe, or steel orplastic bar that is not hollow, but rather is solid.

In FIG. 14, the filling method according to the present embodiment isillustrated in a process flowchart. In the present embodiment, all thesteps of the filling method are common with those of the firstembodiment, except step S25 and its subsequent steps; therefore, thefilling method will be described with regard to only the steps thatdiffer from those of the first embodiment, while a redundant descriptionof the steps common with those of the first embodiment will be omitted.

In step S25, similar to step S25 depicted in FIG. 12, the air cylinder132 retracts the vertically movable rod 142, to thereby insert theretreated rod 230 into the syringe 20. The rod 230 is downwardly movedby the air cylinder 132 until the stop 214 of the rod 230 abuts on thefirst plug 160 that is already present within the syringe 20. The firstplug 160 and the rod 230 within the syringe 20 are thereby positioned inseries with each other, as illustrated in FIG. 13. The advancing limitof the first plug 160 is defined by the abutment on a tip end portion ofthe portion, which forms the discharge passage 57, within the baseportion 56 of the container 12.

Thereafter, the air cylinder 132 is switched to the aforementionedfloating mode; as a result, if the aforementioned assistance by the gasspring 150 is disregarded, the force acting on the first plug 160 fromthe rod 230 a value equal to the summation of the weight of the rod 230and the weight of member(s), which move together with the rod 230, minusthe sliding resistance. This force is a force that urges the first plug160 in the direction towards the base portion 62 of the syringe 20, andis a force that reduces the volume of the first sub-chamber 170.

Thereafter, in step S26, similar to step S27 depicted in FIG. 12, theplunger 22 rises and is pushed into the container 12, as illustrated inFIG. 13. With this, the viscous material 14 is extruded from thecontainer 12 against the force of gravity, to thereby initiate thefilling of the first sub-chamber 170.

In the present embodiment, prior to the filling of the viscous materialinto the syringe 20, air is present within the first sub-chamber 170 ofthe syringe 20; nevertheless, during the filling, the first sub-chamber170 is not evacuated.

However, in the present embodiment as illustrated in FIG. 15, when theviscous material 14 flows from the container 12 into the firstsub-chamber 170 of the syringe 20, air present within the firstsub-chamber 170 is compressed by the in-flowing viscous material 14.

As a result, a pressure differential is generated within the syringe 20,because the first sub-chamber 170 is at a higher pressure than thesecond sub-chamber 172 (at atmospheric pressure), which is incommunication with outside of the syringe 20. Due to this pressuredifferential, air within the first sub-chamber 170 flows into the secondsub-chamber 172 via the radial clearance between the innercircumferential surface 162 of the syringe 20 and the outercircumferential surface of the first plug 160, and consequently, it isdischarged from the opening 68 of the syringe 20 to the outside.

As a result, according to the present embodiment, during the filling ofthe viscous material 14 into the first sub-chamber 170, the air isdischarged from the first sub-chamber 170, and air is prevented frombeing incorporated into the viscous material 14 within the firstsub-chamber 170.

Further, according to the present embodiment, a force is applied to thefirst plug 160 within the syringe 20 by the rod 230 in the directionthat reduces the volume of the first sub-chamber 170. The applied forceis a force that displaces the first plug 160 towards the viscousmaterial 14 that has flowed into the syringe 20.

For these reasons, according to the present embodiment, due to theapplication of the aforementioned force by the rod 230, theabove-mentioned pressure differential is again created and a largerpressure differential is generated within the syringe 20 than if a forcewere not applied by the rod 230. A phenomenon is thereby promoted thatair present within the first sub-chamber 170 flows into the secondsub-chamber 172 through the radial clearance between the innercircumferential surface 162 of the syringe 20 and the outercircumferential surface of the first plug 160.

Thus, according to the present embodiment, in order to prevent air frommixing into the viscous material 14 during the filling of the viscousmaterial 14 from the container 12 into the syringe 20, there is no needto evacuate the inner chambers within the container 12 and the syringe20 (in particular, the chamber within the syringe 20). As a result, itis possible to prevent air from being mixed into the viscous material 14during the filling of the viscous material 14 into the syringe 20,without requiring the provision of a housing that holds both thecontainer 12 and the syringe 20 in an air-tight manner.

Thereafter, the entire first sub-chamber 170, which is in the initialstate depicted in FIG. 13, is filled with the viscous material 14(replacing the air initially present within the first sub-chamber 170with viscous material 14). Subsequently, as the filling of the viscousmaterial 14 continues, the volume of the first sub-chamber 170 increasesand the first plug 160, the rod 230 and the movable frame 136 rise. Athis time, the viscous material 14 within the first sub-chamber 170 isprevented from leaking into the third sub-chamber 200 by the cooperativeaction of its viscosity and the radial clearance between the innercircumferential surface 162 of the syringe 20 and the outercircumferential surface of the first plug 160.

Prior to the filling of the viscous material 14 into the syringe 20, thegas spring 150 depicted in FIG. 2 in a compressed state due to themovable frame 136. In response thereto, the gas spring 150 applies aforce to the movable frame 136 lifts the movable frame 136 together withthe rod 230.

Therefore, after the entire first sub-chamber 170, which is in theinitial state depicted in FIGS. 3 and 7, is filled with the viscousmaterial 14, and when the volume of the first sub-chamber 170 furtherincreases, it is possible to raise the first plug 160, the rod 230 andthe movable frame 136 without increasing much the pressure of theviscous material 14 within the first sub-chamber 170. In other words, instep S27 in the present embodiment, the lifting of the rod 230 and themovable frame 136 is mechanically assisted by the gas spring 152.

Thereafter, when the plunger 22 bottoms out in the container 12, in stepS28, the rod 230 is raised with the first plug 160 remaining as iswithin the syringe 20, and the rod 230 is retracted from the syringe 20,similar to step S29 depicted in FIG. 12.

Subsequently, in step S29, the syringe set is removed from the container12 and the filling device 10, similar to step S30 depicted in FIG. 12.Thereafter, in step S31, the container set is removed from the fillingdevice 10, similar to step S30 depicted in FIG. 12. Then, thetransferring and filling of the viscous material 14 from the onecontainer 12 to the one the syringe 20 is completed.

Next, a third embodiment of the present invention will be described. Thepresent embodiment, however, is similar to the first or secondembodiment, except for the container set; therefore, the presentembodiment will be described in detail with regard to only the containerset, while a redundant description of the elements common with those ofthe first or second embodiment will be omitted.

In FIG. 16, the container set that is used for performing the fillingmethod according to the present embodiment is illustrated in an explodedview. The container set has a basic structure that is similar to thecontainer set depicted in FIG. 5. However, the container set accordingto the present embodiment differs from the container set depicted inFIG. 5 in that container 250 is constituted by two separable componentsincluding a main body 252 and a plug 254, and that the portion of aplunger 260, which is inserted into the container 250, is not uniform indiameter in the axial direction.

More specifically, the main body 252 is constituted by including thehousing 50, the chamber 52, the opening 54 and the base portion 56. Athrough hole 270 that extends longitudinally with a circularcross-section is formed in the central portion of the base portion 56.The plug 254 is constituted by integrally including a base plate 280, anengagement shaft 282 that extends from one of the two faces of the baseplate 280, and a coupling shaft 284 that extends from the opposite faceof the base plate 280. The plug 254 is made of a synthetic resin such asTeflon (registered trademark), but the plug 254 may be alternativelymade of other materials. The plug 254 has a through hole 286 thatsimultaneously penetrates through those three portions 280, 282 and 284.

When the plug 254 is affixed to the main body 252, the engagement shaft282 fits into the through hole 270 of the base portion 56. The couplingshaft 284 is used to couple the container 250 with the base portion 62of the syringe 20 in a substantially air-tight manner; morespecifically, the coupling shaft 284 is fitted into the tubular portion64 of the base portion 62. In the present embodiment, a male thread isformed on the outer circumferential surface of the coupling shaft 284,while a female thread is formed on the inner circumferential surface ofthe tubular portion 64; the coupling shaft 284 and the tubular portion64 are connected by screwing them together.

The plug 254 is removably attached to the main body 252, to maintainthis attachment, the plug 254 is fastened to the main body 254 by beingscrewed together. The container 250 is completed by attaching the plug254 to the main body 252, and in this state, the viscous material 14 istransferred from the chamber 52 of the container 250 into the syringe20. In other words, the through hole 286 provides the same function asthe discharge passage 57.

Thus, in the present embodiment, the plug 254 is separable from the mainbody 252. In addition, because the plug 254 is commonly used for aplurality of individual syringes 20, the coupling shaft 284 quicklybecomes worn out. Consequently, according to the present embodiment,replacement of the plug 254 can be performed independently of thereplacement of the main body 252, which prevents the main body 252 frombeing unnecessarily replaced when the plug 254 requires replacement.

As illustrated in FIG. 16, the main body 58 of the plunger 260 has a tipend portion 290 having a hemispheric shape, a base end portion 292adjacent to the engagement portion 59, and an intermediate portion 294located therebetween. The tip end portion 290, the base end portion 292and the intermediate portion 294 each have a circular cross-section, butthe diameter D2 of the tip end portion 290 is smaller than the diameterD1 of the base end portion 292. In addition, the intermediate portion294 is tapered such that its diameter changes from a value equal to thediameter D2 of the tip end portion 290 to a value equal to the diameterD1 of the base end portion 292.

Because the diameter D1 of the base end portion 292 is substantiallyequal to the diameter of the chamber 52 of the main body 252 (equal tothe diameter of the opening 54), when the base end portion 292 isinserted and held in the chamber 52, there is only a small,circumferentially-extending radial clearance CL1 between an outercircumferential surface of the base end portion 292 and an innercircumferential surface of the chamber 52.

Due to this, in this state, even if viscous material 14 is presentwithin the chamber 52 and air is present between a rear face of theviscous material 14 within the chamber 52 and a tip end face of theplunger 260, neither the viscous material 14 nor the air substantiallyleaks to the outside via the clearance CL1.

In contrast, when the tip end portion 290 is inserted and held in thechamber 52, a clearance CL2 having a radial dimension larger than thatof the clearance CL1 is created between the outer circumferentialsurface of the base end portion 292 and the inner circumferentialsurface of the chamber 52. For this reason, in this state, leakage ofsome of the viscous material 14 and air present between the rear face ofthe viscous material 14 within the chamber 52 and the tip end face ofthe plunger 260 to the outside via the clearance CL2 is facilitated.

Incidentally, when the plunger 260 is caused to be inserted into thecontainer 250 while the chamber 52 is filled with the viscous material14, the plunger 260 is inserted into the chamber 52 together with theair located in front of the plunger 260. When the plunger 260 reachesits advancing limit within the container 250, and when the transfer ofall the viscous material 14 from the container 250 to the syringe 20 hasbeen completed, the air, which has entered into the chamber 52 as aresult of the introduction of the plunger 260, will be present in thefirst sub-chamber 170 of the syringe 20.

As a result, the viscous material 14 as well as air is present withinthe first sub-chamber 170 of the syringe 20. When this air is present,the operator will be inconvenienced when attempting to operate theaforementioned dispenser gun to dispense individual doses of the viscousmaterial 14, because the dispenser gun the dispenser gun will dispenseonly air at the beginning of the dispensing process, and it will notdispense a dose of the viscous material 14 which must be dispensed;also, the air within the first sub-chamber 170 can be trapped within theviscous material 14, individual doses of the viscous material 14, whichhave been dispensed from the dispenser gun and applied to a targetobject, can trap air bubbles, and the trapped air bubbles can createvoids within the doses of the viscous material 14 applied to the targetobject.

In contrast, in the present embodiment, when the insertion of theplunger 260 into the container 250 starts, the tip end portion 290 firstenters the container 250; at this time, the clearance CL2 is formedbetween the outer circumferential surface of the tip end portion 290 andthe inner circumferential surface of the chamber 52. If air is presentbetween the tip end portion 290 and the viscous material 14 held in thechamber 52, the air will be displaced by the advancing tip end portion290, resulting in discharge of the air to the outside via the clearanceCL2.

At this time, while not only the air but also the viscous material 14are displaced by the advancing tip end portion 290, the viscous material14 is not easily expunged via the clearance CL2 due to its viscosity. Inother words, the clearance CL2 serves as a filter that permits only theair to be expunged though the filter.

The maximum possible volume of air that enters the chamber 52 when theplunger 260 is inserted into the chamber 250 can be estimated with acertain degree of precision, depending on the profile (typically, flat)of the rear end of the mass of the viscous material 14 that fills thechamber 52, the viscosity (ease of changing material shape) of theviscous material 14 that fills the chamber 52, the profile of the tipend portion 290, and the area of the cross section of the plunger 260.

Therefore, it is possible to estimate the required stroke of the plunger260 to expunge via the clearance CL2 substantially all of the maximumpossible volume of air that has entered into the chamber 52 from thechamber 250. The axial length of the tip end portion 290 is pre-set insuch a manner that, when the predicted stroke is reached, theintermediate portion 294 enters into the container 250, and thereafter,the base end portion 292 starts to enter into the container 250. Afterthe base end portion 292 enters the chamber 52, the viscous material 14is prevented from being expunged from the chamber 52.

Therefore, according to the present embodiment, by partially orcompletely preventing the ingress of air into the container 250 due tothe plunger 260 being inserted into the container 250, the possibilityis eliminated that air rather than the viscous material 14 will bedispensed from the dispenser gun and that voids will form within theviscous material 14, which has been dispensed from the dispenser gun andapplied to the target object.

The present specification provides a complete description of thecompositions of matter, methodologies, systems and/or structures anduses in exemplary implementations of the presently-described technology.Although various implementations of this technology have been describedabove with a certain degree of particularity, or with reference to oneor more individual implementations, those skilled in the art could makenumerous alterations to the disclosed implementations without departingfrom the spirit or scope of the technology thereof. Furthermore, itshould be understood that any operations may be performed in any order,unless explicitly claimed otherwise or a specific order is inherentlynecessitated by the claim language. It is intended that all mattercontained in the above description and shown in the accompanyingdrawings shall be interpreted as illustrative only of particularimplementations and are not limiting to the embodiments shown. Changesin detail or structure may be made without departing from the basicelements of the present technology as defined in the following claims.

1.-8. (canceled)
 9. A method for transferring a viscous material into acartridge to fill the cartridge, the cartridge including: a syringehaving an inner space defined by an inner circumferential surface; and aplug in the syringe dividing the syringe inner space into a firstsub-chamber in front of the plug configured to be filled with theviscous material, and a second sub-chamber behind the plug, wherein aradial clearance exists between the inner circumferential surface of thesyringe and an outer circumferential surface of the plug, the radialclearance being dimensioned to prevent the viscous material from flowingfrom the first sub-chamber into the second sub-chamber, the methodcomprising: transferring the viscous material from the container intothe first sub-chamber to fill the first sub-chamber while allowing airinitially present within the first sub-chamber to flow into the secondsub-chamber via the radial clearance in a manner that substantiallyprevents the air from mixing into the viscous material within the firstsub-chamber; and after at least some of the air initially present withinthe first sub-chamber is replaced with the viscous material, flowing afirst volume of the viscous material into but not through the radialclearance such that the viscosity of the first volume of the viscousmaterial and the radial clearance cooperate to block a flow of a secondvolume of the viscous material into the radial clearance and prevent thesecond volume of the viscous material from leaking from the firstsub-chamber into the second sub-chamber.
 10. The method according toclaim 9, further comprising applying a force to the plug in a directionfrom the second sub-chamber toward the first sub-chamber.
 11. A methodfor transferring a viscous material from a container into a dispensingsyringe to fill the dispensing syringe, the method comprising: insertinginto the syringe a plug configured to permit gas flow in one directionsuch that the plug divides a chamber within the syringe into a firstsub-chamber and a second sub-chamber; inserting a rod into the syringesuch that the rod engages the plug; and extruding the viscous materialfrom the container into the first sub-chamber of the syringe to fill thefirst sub-chamber of the syringe.
 12. The method according to claim 11,further comprising: inserting a plunger into the container; andconnecting the container to the syringe, wherein extruding the viscousmaterial comprises pushing the plunger within the container.
 13. Themethod according to claim 11, wherein the plug blocks a flow of theviscous material through a clearance between an inner circumferentialsurface of the syringe and an outer circumferential surface of the plugin a first direction from the first sub-chamber toward the secondsub-chamber and in a second direction from the second sub-chamber towardthe first sub-chamber due to a viscosity of the viscous material. 14.The method according to claim 11, wherein, after the first sub-chamberis filled with the viscous material and the air initially present withinthe first sub-chamber is replaced with the viscous material,transferring additional viscous material into the first sub-chamber toincrease the volume of the first sub-chamber and move the plug and therod away from the container, whereby the viscous material within thefirst sub-chamber is prevented from leaking into the second sub-chamberby the cooperative action of a viscosity of the viscous material and aradial clearance between an inner circumferential surface of the syringeand an outer circumferential surface of the plug.
 15. A syringe forreceiving a viscous material from a container, the syringe comprising: asyringe housing; a syringe inner chamber defined within the syringehousing for receiving the viscous material; and a plug mounted in thesyringe inner chamber, the plug separating the syringe inner chamberinto a first sub-chamber and a second sub-chamber, the first sub-chamberbeing located between the second sub-chamber and the container, the plugbeing spaceable from the syringe housing by a radial clearance inresponse to a pressure difference between the first sub-chamber and thesecond sub-chamber, the radial clearance being configured to allow aflow of air initially present in the first sub-chamber from the firstsub-chamber to the second sub-chamber while preventing a flow of viscousmaterial in a direction from the first sub-chamber to the secondsub-chamber, and a rod disposed in the syringe in engagement with theplug and configured to apply a force to the plug in a direction from thesecond sub-chamber toward the first sub-chamber.